Offer To Purchase For Cash All Outstanding Shares Of Common Stock of Exa Corporation at $24.25 Per Share by 3DS Acquisition 3 Corp., Dassault Systemes Simulia Corp. and Dassault Syst`emes S.E. THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 5:00 P.M., NEW YORK CITY TIME, ON NOVEMBER 9, 2017 UNLESS THE OFFER IS EXTENDED. 3DS Acquisition 3 Corp., a Delaware corporation (‘‘Purchaser’’) and a direct wholly owned subsidiary of Dassault Systemes Simulia Corp., a Rhode Island corporation (‘‘Parent’’), which is an indirect wholly owned subsidiary of Dassault Systemes` S.E., a European Company incorporated in France (‘‘Dassault Syst`emes’’), is offering to purchase all outstanding shares of common stock, par value $0.001 per share (each, a ‘‘Share’’ and collectively, the ‘‘Shares’’), of Exa Corporation, a Delaware corporation (‘‘Exa’’), at a price of $24.25 per Share (the ‘‘Offer Price’’), payable net to the holder thereof in cash, without interest, subject to any withholding of taxes required by applicable law, upon the terms and subject to the conditions set forth in this Offer to Purchase (as it may be amended or supplemented, this ‘‘Offer to Purchase’’) and in the related Letter of Transmittal (as it may be amended or supplemented, the ‘‘Letter of Transmittal’’ and, together with this Offer to Purchase, the ‘‘Offer’’). The Offer is being made pursuant to the Agreement and Plan of Merger, dated as of September 27, 2017 (as it may be amended, restated or supplemented from time to time, the ‘‘Merger Agreement’’), among Parent, Purchaser and Exa. Pursuant to the Merger Agreement, as soon as practicable following the consummation of the Offer and the satisfaction or, to the extent permitted by applicable law, waiver of each of the applicable conditions set forth in the Merger Agreement, pursuant to Section 251(h) of the Delaware General Corporation Law (the ‘‘DGCL’’), Purchaser and Exa will merge (the ‘‘Merger’’), with Exa as the surviving corporation in the Merger continuing as a direct wholly owned subsidiary of Parent. As a result of the Merger, each outstanding Share (other than Shares (a) held in the treasury of Exa or owned by any direct or indirect wholly owned subsidiary of Exa, (b) owned by Purchaser, Parent or any direct or indirect wholly owned subsidiary of Parent, and (c) in respect of which appraisal rights are perfected in accordance with Section 262 of the DGCL) will at the effective time of the Merger be canceled and converted into the right to receive an amount equal to the Offer Price, payable net to the holder thereof in cash, without interest, subject to any withholding of taxes required by applicable law. EXA’S BOARD OF DIRECTORS RECOMMENDS THAT YOU TENDER ALL OF YOUR SHARES INTO THE OFFER. On September 27, 2017, the Exa Board of Directors (the ‘‘Exa Board’’) unanimously: (i) determined that the Merger Agreement and the transactions contemplated thereby are fair to and in the best interests of Exa and its stockholders; (ii) declared that the Merger Agreement and the transactions contemplated thereby, including the Offer and the Merger, are advisable; (iii) approved the execution, delivery and performance by Exa of the Merger Agreement and the consummation of the transactions contemplated thereby; (iv) resolved that the Merger will be effected under Section 251(h) of the DGCL; and (v) subject to the other terms and conditions of the Merger Agreement, resolved to recommend that the holders of Shares accept the Offer and tender their Shares to Purchaser in the Offer. Accordingly, and for other reasons described in more detail in Exa’s Solicitation/Recommendation Statement on Schedule 14D-9 that is being filed with the Securities and Exchange Commission (the ‘‘SEC’’) and, together with this Offer to Purchase, the Letter of Transmittal and other related materials, mailed to the stockholders of Exa in connection with the Offer, the Exa Board unanimously recommends that Exa’s stockholders accept the Offer and tender their Shares to Purchaser pursuant to the Offer. There is no financing condition to the Offer. The Offer is, however, subject to the satisfaction of the Minimum Condition (as defined in the ‘‘Introduction’’ to the Offer to Purchase) and the other conditions described in Section 15—‘‘Conditions of the Offer’’ of this Offer to Purchase. A summary of the principal terms of the Offer appears in Section 1—‘‘Terms of the Offer’’ of this Offer to Purchase. You should read this entire document carefully before deciding whether to tender your Shares. Questions and requests for assistance may be directed to Alliance Advisors LLC, the Information Agent, at its address and telephone number set forth below and on the back cover of this Offer to Purchase. Additional copies of this Offer to Purchase, the related Letter of Transmittal, the Notice of Guaranteed Delivery (as it may be amended or supplemented, the ‘‘Notice of Guaranteed Delivery’’) and other related materials may be obtained from the Information Agent or at the website maintained by the SEC at www.sec.gov. Stockholders of Exa also may contact their broker, dealer, commercial bank, trust company or other nominee for copies of these documents. The Information Agent for the Offer is: 6OCT201719250591 Alliance Advisors LLC 200 Broadacres Drive, 3rd Floor Bloomfield, NJ 07003 Call Collect: (973) 873-7780 or Call Toll-Free: (888) 991-1293 Email: [email protected] October 12, 2017 IMPORTANT Stockholders of Exa desiring to tender Shares must: 1. For Shares that are registered in the name of a broker, dealer, commercial bank, trust company or other nominee: • contact the broker, dealer, commercial bank, trust company or other nominee and request that the broker, dealer, commercial bank, trust company or other nominee tender the Shares to Purchaser before the expiration of the Offer. 2. For Shares that are registered in the stockholder’s name and held in book-entry form: • complete and sign the Letter of Transmittal (or a facsimile thereof) in accordance with the instructions in the Letter of Transmittal or prepare an Agent’s Message (as defined in Section 2—‘‘Acceptance for Payment and Payment for Shares’’ of this Offer to Purchase); • if using the Letter of Transmittal, have the stockholder’s signature on the Letter of Transmittal guaranteed if required by Instruction 1 of the Letter of Transmittal; • deliver an Agent’s Message or the Letter of Transmittal (or a facsimile thereof), properly completed and duly executed, and any other required documents to Computershare Trust Company, N.A., the depositary for the Offer (the ‘‘Depositary’’), at its address on the back of this Offer to Purchase before the expiration of the Offer; and • transfer the Shares through book-entry transfer into the account of the Depositary before the expiration of the Offer. 3. For Shares that are registered in the stockholder’s name and held as physical certificates: • complete and sign the Letter of Transmittal (or a facsimile thereof) in accordance with the instructions in the Letter of Transmittal; • have the stockholder’s signature on the Letter of Transmittal guaranteed if required by Instruction 1 to the Letter of Transmittal; and • deliver the Letter of Transmittal (or a facsimile thereof) properly completed and duly executed, the certificates for such Shares and any other required documents to the Depositary, at its address on the back of this Offer to Purchase before the expiration of the Offer. The Letter of Transmittal, the certificates for the Shares and any other required documents must be received by the Depositary before the expiration of the Offer, unless the procedures for guaranteed delivery described in Section 3—‘‘Procedures for Accepting the Offer and Tendering Shares’’ of this Offer to Purchase are followed. The method of delivery of Shares, the Letter of Transmittal and all other required documents, including delivery through the Depositary, is at the election and risk of the tendering stockholder. * * * * * This Offer to Purchase and the related Letter of Transmittal contain important information and you should read both carefully and in their entirety before making a decision with respect to the Offer. The Offer has not been approved or disapproved by the SEC or any state securities commission nor has the SEC or any state securities commission passed upon the fairness or merits of or upon the accuracy or adequacy of the information contained in this Offer to Purchase. Any representation to the contrary is unlawful. SUMMARY TERM SHEET ................................................... 1 INTRODUCTION .......................................................... 11 THE TENDER OFFER ...................................................... 15 1. Terms of the Offer ............................................. 15 2. Acceptance for Payment and Payment for Shares ....................... 17 3. Procedures for Accepting the Offer and Tendering Shares ................. 18 4. Withdrawal Rights ............................................. 21 5. Material United States Federal Income Tax Consequences ................ 22 6. Price Range of the Shares; Dividends ............................... 25 7. Possible Effects of the Offer on the Market for the Shares; NASDAQ Listing; Exchange Act Registration; Margin Regulations ........................ 25 8. Certain Information Concerning Exa ................................ 27 9. Certain Information Concerning Dassault Systemes,` Parent and Purchaser ..... 27 10. Background of the Offer; Past Contacts or Negotiations with Exa ..........